"The Flash" features the Barry Allen version of the character from DC Comics, who was created by Robert Kanigher, John Broome and Carmine Infantino. "Arrow" executive producers Greg Berlanti and Andrew Kreisberg are at the helm of the series, and co-wrote the pilot script with DC chief creative officer Geoff Johns. It also stars Jesse L. Martin, Rick Cosnett, Danielle Panabaker, Candice Patton, Carlos Valdes, Tom Cavanaugh, John Wesley Shipp, Michelle Harrison and Patrick Sabongui.

"iZombie" comes from "Veronica Mars" creator Rob Thomas and Diane Ruggiero, and is loosely based on the Vertigo series by Chris Roberson and Mike Allred. It also stars Malcolm Goodwin, Alexandra Krosney, David Anders, Robert Buckley, Nora Dunn and Ruhul Kohli.